Notably, the expression levels of p16INK4a (CDKN2A) and several SASP factor genes, such as IL32, CXCL14 and MMP1029–31, were increased in the lung cells of patients with severe COVID-19 as compared with those of healthy individuals, especially in basal cells and, to a lesser extent, in ciliated cells (Fig. 3d and Supplementary Fig. 1). This evidence concerns the gene CDKN2A and COVID-19.